Optimization Of Groundwater Remediation With New Efficient Parallel Algorithm For Global Optimization

Application of optimization algorithm to PDE modeling groundwater remediation can greatly reduce remediation cost. However, groundwater remediation analysis requires a computational expensive simulation, therefore, effective parallel optimization could potentially greatly reduce computational expense. The optimization algorithm used in this research is Parallel Stochastic radial basis function. This is designed for global optimization of computationally expensive functions with multiple local optima and it does not require derivatives. In each iteration of the algorithm, an RBF is updated based on all the evaluated points in order to approximate expensive function. Then the new RBF surface is used to generate the next set of points, which will be distributed to multiple processors for evaluation. The criteria of selection of next function evaluation points are estimated function value and distance from all the points known. Algorithms created for serial computing are not necessarily efficient in parallel so Parallel Stochastic RBF is different algorithm from its serial ancestor. The application for two Groundwater Superfund Remediation sites, Umatilla Chemical Depot, and Former Blaine Naval Ammunition Depot. In the study, the formulation adopted treats pumping rates as decision variables in order to remove plume of contaminated groundwater. Groundwater flow and contamination transport is simulated with MODFLOW-MT3DMS. For both problems, computation takes a large amount of CPU time, especially for Blaine problem, which requires nearly fifty minutes for a simulation for a single set of decision variables. Thus, efficient algorithm and powerful computing resource are essential in both cases. The results are discussed in terms of parallel computing metrics i.e. speedup and efficiency. We find that with use of up to 24 parallel processors, the results of the parallel Stochastic RBF algorithm are excellent with speed up efficiencies close to or exceeding 100%.

RST: Reuse through Speculation on Traces

In this thesis, we present a novel approach to combine both reuse and prediction of dynamic sequences of instructions called Reuse through Speculation on Traces (RST). Our technique allows the dynamic identification of instruction traces that are redundant or predictable, and the reuse (speculative or not) of these traces. RST addresses the issue, present on Dynamic Trace Memoization (DTM), of traces not being reused because some of their inputs are not ready for the reuse test. These traces were measured to be 69% of all reusable traces in previous studies. One of the main advantages of RST over just combining a value prediction technique with an unrelated reuse technique is that RST does not require extra tables to store the values to be predicted. Applying reuse and value prediction in unrelated mechanisms but at the same time may require a prohibitive amount of storage in tables. In RST, the values are already stored in the Trace Memoization Table, and there is no extra cost in reading them if compared with a non-speculative trace reuse technique. . The input context of each trace (the input values of all instructions in the trace) already stores the values for the reuse test, which may also be used for prediction. Our main contributions include: (i) a speculative trace reuse framework that can be adapted to different processor architectures; (ii) specification of the modifications in a superscalar, superpipelined processor in order to implement our mechanism; (iii) study of implementation issues related to this architecture; (iv) study of the performance limits of our technique; (v) a performance study of a realistic, constrained implementation of RST; and (vi) simulation tools that can be used in other studies which represent a superscalar, superpipelined processor in detail. In a constrained architecture with realistic confidence, our RST technique is able to achieve average speedups (harmonic means) of 1.29 over the baseline architecture without reuse and 1.09 over a non-speculative trace reuse technique (DTM).

Pompidou & Pompeia: a parallel between the management strategies of two cultural institutions in the French and Brazilian contexts

A presente pesquisa foi conduzida na forma de um estudo de caso de duas instituições culturais no contexto francês e brasileiro. O Centro Pompidou é um projeto presidencial de museu financiado pelo Estado, com a missão de tornar a arte moderna em todas as suas expressões acessíveis ao público em geral. O Sesc Pompeia é um centro multidisciplinar de cultura e esporte - financiado pelo dinheiro dos impostos e administrado pela Federação do Comércio . O Sesc Pompéia é dedicado à oferta de educação informal através do cultivo da mente e do corpo. O estudo examina se as teorias de dependência de recursos e de poder podem ser utilizadas para conceituar a relação que o Centro Pompidou e do Sesc Pompéia tem com seus stakeholders financeiros. Mais especificamente, será discutido em que medida o grau de dependência influencia a estratégia de gestão das instituições. O objetivo é de responder a pergunta seguinte: quais são as estratégias que as instituições adotam para reduzir sua dependência com relação a seus principais stakeholders financeiros? Finalmente algumas implicações práticas de gestão serão elaboradas a partir do paralelo entre as estratégias das duas instituições.

Parallel Cyclostationarity-Exploiting Algorithm for Energy-Efficient Spectrum Sensing

The evolution of wireless communication systems leads to Dynamic Spectrum Allocation for Cognitive Radio, which requires reliable spectrum sensing techniques. Among the spectrum sensing methods proposed in the literature, those that exploit cyclostationary characteristics of radio signals are particularly suitable for communication environments with low signal-to-noise ratios, or with non-stationary noise. However, such methods have high computational complexity that directly raises the power consumption of devices which often have very stringent low-power requirements. We propose a strategy for cyclostationary spectrum sensing with reduced energy consumption. This strategy is based on the principle that p processors working at slower frequencies consume less power than a single processor for the same execution time. We devise a strict relation between the energy savings and common parallel system metrics. The results of simulations show that our strategy promises very significant savings in actual devices.

Bifurcation Analysis of a Van der Pol-Duffing Circuit with Parallel Resistor

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)